The overall goal of this NIDDK Mentored Research Scientist Development Award is to provide a structured scientific and educational environment for Dr. Jennifer McDonald to transition to an independent clinical researcher focused on optimizing imaging studies utilizing iodinated contrast media. This proposal outlines a five-year training plan at the Mayo Clinic under the primary mentorship of Dr. David Kallmes and an Advisory Committee comprised of accomplished clinicians and researchers in the fields of radiology, nephrology, and statistics. The focus of this current proposal is to perform an innovative and detailed study of the putative causative role of contrast media in acute kidney injury (AKI). The widely held belief that contrast media leads directly to renal injury, an entity termed contrast induced nephropathy (CIN), frequently impacts clinical decision making among the millions of patients who undergo contrast-enhanced procedures in the United States annually. These procedures are frequently delayed or withheld in patients considered to be at high risk of developing CIN, potentially compromising patient care. While CIN is widely accepted as a meaningful clinical entity, the true incidence and clinical significance of this complication s not fully understood. Dr. McDonald's preliminary retrospective study of over 150,000 contrast-enhanced and non-contrast CT scans suggests that serum creatinine (SCr), the most commonly used diagnostic marker for CIN, is nonspecific and cannot differentiate between CIN and contrast-independent renal injury. As such, there is a critical need to identify improved markers to more accurately characterize CIN. The goal of this research proposal is to evaluate potential biologic and radiologic diagnostic markers to better characterize AKI following contrast procedures. The specific aims of this project are to 1) perform a rigorous analysis of matched contrast-enhanced and non- contrast CT scan recipients with stage 3 chronic kidney disease to determine the incidence of AKI following intravenous contrast administration, 2) determine the diagnostic potential of newer renal biomarkers in a prospective controlled trial, and 3) determine the diagnostic potential of dual energy CT following percutaneous coronary intervention or CT scan to differentiate between CIN and embolic AKI. This research will be facilitated by the Mayo Clinic's exceptional clinical and research environment dedicated toward improving patient care. Dr. McDonald's background in laboratory medicine and patient database analysis makes her particularly suited for this research. In addition to the above aims, Dr. McDonald will 1) develop a strong knowledge base in nephrology and radiology by attending relevant rounds, seminars, and national conferences, 2) enhance her statistics background through coursework and mentoring, 3) attend workshops focused on writing grants and publications, and 4) submit an R01 application expanding upon the findings from this proposal. This proposal will lead to an improved understanding of the diagnostic potential of newer markers for CIN and will enable Dr. McDonald to establish herself as a successful, independent researcher.